3G and 4G connections are highly dependent on signal strength and signal quality.  This article provides recommended values for broadband connectivity.

CX111 supports both 3G and 4G modems. The signal strength and signal quality both contribute to performance and in extreme cases, connectivity.

Signal strength and signal quality can affect data performance and basic connectivity.  This article breaks down each, and also provides recommended values for broadband connectivity.

 

Signal Strength

• Influences connection to the cellular tower
• Represented by RSSI, which is measured in dBm
• RSSI is a negative value, and the closer to 0, the stronger the signal

NOTE: Signal Strength must be reviewed by the numeric values, ie. -dBm. The number of signal bars displayed by devices may give inaccurate perception of actual signal strength.

 

Signal Quality

• Influences data throughput speeds on mobile broadband networks
• Represented by signal noise ratios, measured in dBm
• Noise ratio representation varies by mobile broadband technology:
  • LTE - SINR
    • SINR is a positive dBm value
    • Higher SINR numbers = better quality connection
  • WiMAX - CINR
    • CINR is a positive dBm value.
    • Higher CINR numbers = better quality connection
  • CDMA/EVDO - EC/IO
    • EC/IO is a negative dBm value. Values closer to 0 are stronger signals.
    • Lower EC/IO ‘numbers’ = better quality connection

 

Minimum Signal Values

	Signal Strength		Signal Quality
Technology	Most Modems (RSSI)	Exceptions* (RSSI or bars)	LTE (SINR)	WiMAX (CINR)	EV-DO (EC/IO)
Minimum Signal Values	dBm > -85	dBm > -64	dBm > 7	dBm > 9	dBm > -10

 

• Exceptions apply to the following modems in LTE mode: Pantech UML 290, Novatel 551L
• LG VL600 does not report db values, only bars.  LG VL600 requires a minimum of 2 bars.

 

Disclaimers

1. Both Signal Strength and Signal Quality must be considered for successful cellular data connection.
2. Measured or reported values vary by modem, carrier, and network environment.
3. There is no black/white answer to what constitutes a successful connection.
4. Although signal strength may appear to be adequate, throughput speeds may vary due to dependencies on cellular tower loads.